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[SRU,Focal,8/9] ALSA: hda: hdmi - Keep old slot assignment behavior for Intel platforms

Message ID 20200812055822.5853-9-hui.wang@canonical.com
State New
Headers show
Series alsa/hdmi: support nvidia mst hdmi/dp audio | expand

Commit Message

Hui Wang Aug. 12, 2020, 5:58 a.m. UTC
From: Takashi Iwai <tiwai@suse.de>

BugLink: https://bugs.launchpad.net/bugs/1867704

The commit 609f5485344b ("ALSA: hda: hdmi - preserve non-MST PCM
routing for Intel platforms") tried to restore the old behavior wrt
assignment of the PCM slot for Intel platforms, but this didn't do it
right.  As found in the later discussion, a positive pipe id on Intel
platforms can be passed for single monitor attachment case.

This patch reverts the previous attempt and applies a simpler
workaround instead.  Actually, for Intel platforms, we can handle as
if per_pin->dev_id=0, assign the primary slot at the first try.  This
assures the compatible behavior with the previous versions regarding
the slot assignment.

Fixes: 609f5485344b ("ALSA: hda: hdmi - preserve non-MST PCM routing for Intel platforms")
Link: https://lore.kernel.org/r/20191203154105.30414-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
(backported from commit 643a2cc99b53c13d90c02dc344f780ba9a89e012)
Signed-off-by: Hui Wang <hui.wang@canonical.com>
 sound/pci/hda/patch_hdmi.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)
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diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index f48d3e8ae689..2e6d3e48d73b 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -1370,21 +1370,18 @@  static int hdmi_find_pcm_slot(struct hdmi_spec *spec,
 	 * with the legacy static per_pin-pcm assignment that existed in the
 	 * days before DP-MST.
+	 * Intel DP-MST prefers this legacy behavior for compatibility, too.
+	 *
 	 * per_pin of m!=0 prefers to get pcm=(num_nids + (m - 1)).
-	if (per_pin->dev_id == 0) {
+	if (per_pin->dev_id == 0 || is_haswell_plus(per_pin->codec)) {
 		if (!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap))
 			return per_pin->pin_nid_idx;
 	} else {
 		i = spec->num_nids + (per_pin->dev_id - 1);
 		if (i < spec->pcm_used && !(test_bit(i, &spec->pcm_bitmap)))
 			return i;
-		/* keep legacy assignment for dev_id>0 on Intel platforms */
-		if (is_haswell_plus(per_pin->codec))
-			if (!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap))
-				return per_pin->pin_nid_idx;
 	/* have a second try; check the area over num_nids */